1. Field of the Invention
This invention relates to a shock absorber, and more particularly to a shock absorber incorporating improved dampening response mechanisms and more specifically to a shock absorber having a versatile adjustable response mechanism for tuning the performance of the shock absorber apparatus.
2. Description of Related Art
Shock absorber systems have been in use for damping the reaction forces experienced with wheeled vehicles throughout the use of the wheel as a means of transport. Shock absorbers are well known in the art and have been used successfully for many years to improve the safety and handling of many types of vehicles. The design of the shock absorber has often been challenging due to the nature of the dynamic motion of a vehicle as it travels over widely varying terrain and driving conditions. Shock absorber performance, though improved over the last few decades, is still far from optimum. Often, the constraints and criteria used in the design of a shock absorber are counter to one another, and force the designer to balance tradeoffs. The result is a shock absorber having performance that often delivers compromising results.
In certain applications, shock absorber systems are taken to extremes, providing even further challenges for the designer. For example, in the field of off-road motorcycle racing, a shock absorber is exposed to widely varying conditions as the vehicle is raced along a course of travel. Furthermore, the performance of the shock absorber system can make a dramatic impact on the safety and performance of the motorcycle.
For optimum performance, the response of a shock absorber often must be tuned or adjusted for the conditions in which it will be used. However, many shock absorber systems available on the market today have a limited tuning capability. Further, those with an adjusting or tuning capability, are often difficult to adjust, resulting in mal-adjustments of the shock absorber which degrades the performance even further.
The motorcycle shock absorber is relied upon by riders to provide comfort and stability as well as to enhance the performance of the motorcycle. One of the preferences of riders over rough and varied terrain, is to have the responsive handling while preventing the bone jarring jolts to the rider created when the motorcycle impacts into bumps on the terrain. In the motorcycle application, the shock absorber must provide a steady and consistent ride over flat terrain. The flat terrain will not create instantaneous jarring reaction forces. The shock absorber will react to the flat terrain with low speed control. The piston in the cylinder of the shock absorber will translate in the cylinder at a low speed. The shock absorber is required to provide a steady and consistent ride over moderate terrain. The moderate terrain will create moderate reaction forces that cause the shock absorber to translate at a mid or medium speed. It is desirable for a shock absorber to have mid or medium speed control for the moderate terrain where the shock absorber is required to absorb occasional jolts while maintaining a stiff response over the moderate terrain. In addition, the shock absorber is required to provide a stable and consistent ride over rough and choppy terrain. The rough and choppy terrain will cause instantaneous jarring reaction forces on the shock absorber. The shock absorber will react to the rough and choppy terrain with high speed translation. The shock absorber needs high speed control for the high speed translation. The shock absorber is required to dampen the sudden impact forces without a hard stiff jolt. Unfortunately, up to this point, it has been difficult to realize a shock absorber, having a suitable response for the varying types of terrain cited above.
There have been many attempts to some of these problems with varying degrees of success. For example, U.S. Pat. No. 5,810,128 teaches an improved shock absorber having an improved transition between a first and second damping rates. Yet further, U.S. Pat. No. 6,446,771 provides an improved bleed function and non-return valve arrangement. And further, U.S. Pat. No. 6,116,338 teaches an improved compression stroke valve in an attempt to improve the performance of a shock absorber system.
Several attempts have been made to overcome the deficiencies found in the state-of-the-art shock absorbers by designing support systems which reduce the effects of the inherent deficiencies in state-of-the-art shock absorbers. For example, linkage systems have been incorporated on vehicles to modify the motion experienced by the shock absorber to better match it the vehicle system. Unfortunately, while such attempts improve the performance, they also add cost and weight to the vehicle.
Therefore, it is evident that a versatile and adjustable shock absorber is needed to overcome these and other deficiencies in the prior art. The subject invention for a shock absorber apparatus overcomes the perceived shortcomings and detriments in the prior art apparatuses and is the subject matter of the present application.